Apparatus, system, and method for selective stimulation

Abstract

An implantable neurostimulator system is disclosed, the neurostimulator system comprising a hollow cylindrical electronics enclosure having a top, a bottom, and a side; a coil extending from a first part of the electronics enclosure; and at least one electrode operatively connected to the electronics enclosure.

What is claimed is: 
     
       1. A method of treating sleep apnea using neurostimulation to control a position of a patient's tongue, comprising the steps of:
 implanting an electrode having a plurality of contacts into the patient to electrically couple the plurality of contacts to a Hypoglossal nerve of the patient; 
 implanting an implantable pulse generator (IPG) into a sub-mandibular space of the patient, the IPG being electronically coupled to the electrode; 
 programming the IPG to deliver at least two electric signals to the plurality of contacts during a therapy session without taking into account a timing of respiration; and 
 applying the at least two electric signals via the plurality of contacts to a portion of the Hypoglossal nerve, where one of the at least two electric signals overlaps with another of the at least two electric signals, to stimulate at least two muscles of the tongue to prevent the tongue from blocking an airway during the therapy session, 
 wherein applying the at least two electric signals includes driving each of the plurality of contacts by their own independent current source by field steering; and 
 wherein the field steering uses two electrode contacts, each of the two electrode contacts having a sub-threshold phase current field, wherein the subthreshold phase current of each of the two electrode contacts combine to form an overlapping current field with a supra-threshold current field. 
 
     
     
       2. The method of  claim 1 , wherein the IPG comprising a symmetrical, chevron-shaped molded body having an apex at a distal end of the IPG, a coil at the apex of the chevron-shaped molded body, and an electronics enclosure at least partially integral with the chevron-shaped molded body and proximal to the coil, a first lead extending from the electronics enclosure and along a first leg of the chevron-shaped molded body, and a second lead extending from the electronics enclosure and along a second leg of the chevron-shaped molded body, the first leg extending proximally and laterally from a first side of the electronics enclosure, and the second leg extending proximally and laterally from a second side of the electronics enclosure opposite the first side of the electronics enclosure. 
     
     
       3. The method of  claim 2 , wherein the IPG further comprises: one or more holes along each side of the apex. 
     
     
       4. The method of  claim 3 , wherein the IPG is configured to be able to stimulate a left side Hypoglossal nerve, a right side Hypoglossal nerve, or both the left side and the right side Hypoglossal nerve, regardless of an orientation of the IPG as implanted. 
     
     
       5. The method of  claim 1  further comprising the step of: defining a neural activation volume by applying the at least two electric signals. 
     
     
       6. The method of  claim 5 , wherein the at least two electric signals are applied approximately simultaneously. 
     
     
       7. The method of  claim 5 , wherein at least one of the at least two electric signals is an asymmetric pulse. 
     
     
       8. The method of  claim 1 , wherein the electrode includes a cuff housing and wherein implanting the electrode includes wrapping the cuff housing around a portion of the Hypoglossal nerve. 
     
     
       9. The method of  claim 8 , wherein implanting the electrode includes wrapping the cuff housing around the portion of the Hypoglossal nerve at least once. 
     
     
       10. The method of  claim 1 , wherein each of the at least two electric signals is a pulse train having a frequency between approximately 1 and approximately 100 Hertz. 
     
     
       11. The method of  claim 1 , wherein the at least two electric signals are applied to the Hypoglossal nerve via an open loop system. 
     
     
       12. The method of  claim 1 , wherein the at least two electric signals are applied to a portion of the Hypoglossal nerve to stimulate at least two muscles of the tongue such that the stimulation of one of the at least two muscles of the tongue partially overlaps with the stimulation of another of the at least two muscles of the tongue. 
     
     
       13. The method of  claim 1 , wherein implanting an electrode having a plurality of contacts includes implanting a first electrode having at least one contact and implanting a second electrode having at least one contact. 
     
     
       14. The method of  claim 1 , wherein, applying a stimulus to the two electrode contacts defines a neural activation volume, wherein the neural activation volume is a region equidistant between the two electrode contacts. 
     
     
       15. The method of  claim 14 , wherein the neural activation volume is shifted relative to the two electrode contacts by changing a cathodic phase current of each of the at least two electrode contacts. 
     
     
       16. A method of treating sleep apnea using neurostimulation to control the position of a patient's tongue, comprising the steps of:
 implanting an electrode having a plurality of contacts into the patient to electrically couple the plurality of contacts to a Hypoglossal nerve of the patient; 
 implanting an implantable pulse generator (IPG) including a plurality of current generators into the sub-mandibular space of the patient, the IPG being electronically coupled to the electrode; 
 programming the IPG to deliver at least two electric signals to the plurality of contacts during a therapy session without taking into account a timing of respiration; and 
 applying the at least two electric signals via the plurality of contacts to a portion of the Hypoglossal nerve, where one of the at least two electric signals overlaps with another of the at least two electric signals, to stimulate at least two muscles of the tongue to prevent the tongue from blocking an airway during the therapy session, 
 wherein each of the plurality of contacts is driven by its own one of the plurality of current generators by field steering; and 
 wherein the field steering uses two electrode contacts, each of the two electrode contacts having a sub-threshold phase current field, wherein the subthreshold phase current of each of the two electrode contacts combine to form an overlapping current field with a supra-threshold current field. 
 
     
     
       17. The method of  claim 16  further comprising the step of: defining a neural activation volume by applying the at least two electric signals. 
     
     
       18. The method of  claim 16 , wherein at least one of the at least two electric signals is an asymmetric pulse. 
     
     
       19. The method of  claim 16 , wherein the electrode includes a cuff housing and wherein implanting the electrode includes wrapping the cuff housing around a portion of the Hypoglossal nerve. 
     
     
       20. The method of  claim 16 , wherein the at least two electric signals are applied to the Hypoglossal nerve via an open loop system. 
     
     
       21. The method of  claim 16 , wherein implanting an electrode having a plurality of contacts includes implanting a first electrode having at least one contact and implanting a second electrode having at least one contact.